1. Field of the Invention
The invention relates to communications systems and more particularly to radio or radiotelephone systems in which the call recipient is addressed by either his location or status.
2. Description of Related Art
Telephone systems, both land line and cellular, are known in which a station is identified by a telephone number. An originating user places a call to a recipient station by dialing the telephone number which results in establishment of a connection between the originating station and the recipient station over which users of the telephones at those stations may communicate.
In the area of radio transmission, it is also known to address each station with a unique address.
In the prior art, reverse telephone directories are known for identifying a particular address associated with a telephone number. However, such directories are of use only for fixed locations and cannot be utilized effectively to locate mobile stations or those that are portable, i.e. carried on a person.
Detecting traffic status is currently done by building a network of observers and sensing devices. These networks are cumbersome to administer, and sensing devices, because of their expense, tend to be clustered only around high traffic-problem areas.
Consumers presently rely on commercial radio station traffic reports. These cover only a few major roads/accidents and users must listen to all reports for a large geographic area in order to glean information pertinent to their needs.
Low-power AM transmitters are located in some high traffic problems areas, such as airports. These stations require users to tune their radios to a special frequency (away from the music they may have been enjoying) and typically broadcast either out of date information or just a repeated general information recording.
A feature has been developed that is now appearing in new consumer automobile radar detectors. This system can deliver traffic advisories to all radar-detector-operating cars within a general area. This system, however, is unable to target specific populations, such as all cars north of Page Mill Road traveling south on highway 280. Instead, everyone within a given geography receives the notice. Additionally, cars that are beyond range, but could well use the advisory, are excluded. For example, if highway 280 has been closed because of a spill and will remain so for 2 hours, a driver leaving San Francisco needs to be advised to start off on a different highway. Learning three miles away from the accident, once in radar-detection range, that the highway is closed may be of little use.
Traffic advisories, because of their generalized nature, require giving the same advice/instructions to all vehicles. This limits the ability of traffic advisors to suggest multiple detour routes, instead dumping most or all traffic on a single detour, often resulting in a traffic tie-up almost as severe as the tie-up they are attempting to relieve.
In the area of police work, speeding is currently detected either by police officers directly observing an infraction, with our without radar devices, or by preinstalled remote observation devices, such as cameras or autonomous radar detectors. This results in such spotty enforcement that the police presence has become primarily a deterrent.
Police currently rely solely on visual observation to detect such aberrant driving practices as weaving in and out of traffic while speeding or wandering all over the road due to intoxication.
Police depend on warning sirens and lights, sometimes augmented with a public address system, to communicate to drivers. Drivers, in these cases, have no means of communicating back. Drivers, in rare cases, have been known to talk back to the police by dialing 911 on their radio-telephones. Police also sometimes talk to drivers on CB radios, but, typically, police are unable to establish two-way communications with a potential fugitive. This effectively eliminates the possibility of lowering tensions and opening negotiations, resulting in high-speed chases and resultant death and injury.
Police depend strictly on sirens and lights to warn other drivers during hot pursuit. Since the pursued vehicle may be well ahead of the police car giving chase, and since the perpetrator is unlikely to make use of lights and siren, a great many multiple-car collisions occur during high-speed chases.
Vehicles leaving the scene of a crime can be tracked today only if an officer is in immediate pursuit or if the vehicle is known to contain a transponder device and the identity of the vehicle is known to the police. In other words, a getaway car with no license plate cannot be tracked unless the police arrive quickly.
Typical radio systems today can either broadcast to a wide geographic area or target specific vehicles based on their pre-set identity code. Dispatches cannot be targeted to only those vehicles in a given geographic area.
Currently, automobile occupants are limited in their ability to communicate with the occupants of other vehicles. Certain international signs and signals for happiness and displeasure can be issued, but conversation is only possible, via CB or ham radio, both in use by limited, well-defined populations.